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- Also Known As:
- Serum Iron
- Serum Fe
- Formal Name:
- Iron
- serum

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At a Glance
Why Get Tested?
Along with other iron tests, to determine your blood iron level; along with other tests, to help diagnose iron-deficiency anemia or iron overload
When To Get Tested?
When you have low hemoglobin and hematocrit on a complete blood count (CBC); when your health care practitioner suspects that you may have too little iron (deficiency) or too much iron (overload) in your body
Sample Required?
A blood sample drawn from a vein in your arm
Test Preparation Needed?
You may be instructed to have your blood drawn in the morning and/or fast for 12 hours before sample collection; in this case, only water is permitted. Follow any instructions from your health care practitioner and/or from the laboratory performing the test.
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You may be able to find your test results on your laboratory’s website or patient portal. However, you are currently at Testing.com. You may have been directed here by your lab’s website in order to provide you with background information about the test(s) you had performed. You will need to return to your lab’s website or portal, or contact your healthcare practitioner in order to obtain your test results.
Testing.com is an award-winning patient education website offering information on laboratory tests. The content on the site, which has been reviewed by laboratory scientists and other medical professionals, provides general explanations of what results might mean for each test listed on the site, such as what a high or low value might suggest to your healthcare practitioner about your health or medical condition.
The reference ranges for your tests can be found on your laboratory report. They are typically found to the right of your results.
If you do not have your lab report, consult your healthcare provider or the laboratory that performed the test(s) to obtain the reference range.
Laboratory test results are not meaningful by themselves. Their meaning comes from comparison to reference ranges. Reference ranges are the values expected for a healthy person. They are sometimes called “normal” values. By comparing your test results with reference values, you and your healthcare provider can see if any of your test results fall outside the range of expected values. Values that are outside expected ranges can provide clues to help identify possible conditions or diseases.
While accuracy of laboratory testing has significantly evolved over the past few decades, some lab-to-lab variability can occur due to differences in testing equipment, chemical reagents, and techniques. This is a reason why so few reference ranges are provided on this site. It is important to know that you must use the range supplied by the laboratory that performed your test to evaluate whether your results are “within normal limits.”
For more information, please read the article Reference Ranges and What They Mean.
What is being tested?
Iron is an essential nutrient that, among other functions, is required for the production of healthy red blood cells (RBCs). It is a critical part of hemoglobin, the protein in RBCs that binds oxygen in the lungs and releases it as blood circulates to other parts of the body. The serum iron test measures the amount of iron in the liquid portion of blood.
Serum iron is almost always measured with other iron tests, such as serum ferritin, transferrin and total iron-binding capacity (TIBC). These tests are often ordered at the same time and the results interpreted together to help diagnose and/or monitor iron deficiency or iron overload.
The body cannot produce iron and must absorb it from the foods we eat or from supplements. Once absorbed, it is transported throughout the body by binding to transferrin, a protein produced by the liver.
In healthy people, most of the iron absorbed is incorporated into the hemoglobin inside RBCs. The remainder is stored in the tissues as ferritin or hemosiderin, with additional small amounts used to produce other proteins such as myoglobin and some enzymes.
When the level of iron is insufficient to meet the body’s needs, the iron level in the blood drops and iron stores are depleted. This may occur because:
- Not enough iron is consumed (either foods or supplements)
- The body is unable to absorb iron from the foods eaten in conditions such as celiac disease
- There is an increased need for iron, such as during pregnancy or childhood, or due to a condition that causes chronic blood loss (e.g., peptic ulcer, colon cancer)
Insufficient levels of circulating and stored iron may eventually lead to iron deficiency anemia (decreased hemoglobin). In the early stage of iron deficiency, no physical effects are usually seen and the amount of iron stored may be significantly depleted before any signs or symptoms of iron deficiency develop. If a person is otherwise healthy and anemia develops over a long period of time, symptoms seldom appear before the hemoglobin in the blood drops below the lower limit of normal.
However, as the iron-deficiency progresses, symptoms eventually begin to develop. The most common symptoms of anemia include fatigue, weakness, dizziness, headaches and pale skin.
On the other hand, too much iron can be toxic to the body. Iron blood levels and iron storage increase when more iron is absorbed than the body needs. Absorbing too much iron can lead to progressive accumulation and damage to organs such as the liver, heart, and pancreas. An example of this is hemochromatosis, a genetic disease in which the body absorbs too much iron, even on a normal diet. Additionally, iron overdose can occur when someone consumes more than the recommended amount of iron.
Common Questions
View Sources
Sources Used in Current Review
Devkota, B. (2014 January 17 Updated). Iron. Medscape Drugs and Diseases. Available online at http://emedicine.medscape.com/article/2085704-overview. Accessed on March 2018.
Harper, J. and Conrad, M. (Feb 23, 2018). Iron Deficiency Anemia. Medscape Drugs and Diseases. Available online at http://emedicine.medscape.com/article/202333-overview Accessed on March 2018.
(© 1995– 2018). Iron and Total Iron-Binding Capacity, Serum. Mayo Clinic Mayo Medical Laboratories Available online at http://www.mayomedicallaboratories.com/test-catalog/Clinical+and+Interpretive/34624. Accessed on March 2018.
Genzen, J. (2018 March 2018 updated). Hemochromatosis. ARUP Consult. Available online at https://arupconsult.com/content/hemochromatosis. Accessed on March 2018.
Wintrobe’s Clinical Hematology. 12th ed. Greer J, Foerster J, Rodgers G, Paraskevas F, Glader B, Arber D, Means R, eds. Philadelphia, PA: Lippincott Williams & Wilkins: 2009, pp792-793, 826-827.
Harmening D, Clinical Hematology and Fundamentals of Hemostasis, Fifth Edition, F.A. Davis Company, Philadelphia, 2009, pp 122-127.
Sources Used in Previous Reviews
Corbett, JV. Laboratory Tests & Diagnostic Procedures with Nursing Diagnoses, 4th ed. Stamford, Conn.: Appleton & Lang, 1996. Pp. 34-35, 41-43.
Frey, Rebecca J. Iron Tests. Chapter in: Gale Encyclopedia of Medicine, Edition One, 1999 Gale Research Group, Pg. 1648.
Witte DL, Crosby WH, Edwards CQ, Fairbanks VG, Mitros FA. Practice guideline development task force of the College of American Pathologists.
Boston University Medical Center: Community Outreach Health Information System. Available onlineat http://www.bu.edu/cohis/cardvasc/blood/anemia.htm#prevent.
Lyon, Elaine and Frank, Elizabeth L. Hereditary Hemochromatosis Since Discovery of the HFE Gene. Clinical Chemistry 47:1147-1156 (Jul 2001).
Pagana, K. D. & Pagana, T. J. (© 2007). Mosby’s Diagnostic and Laboratory Test Reference 8th Edition: Mosby, Inc., Saint Louis, MO. Pp 574-577.
Clarke, W. and Dufour, D. R., Editors (© 2006). Contemporary Practice in Clinical Chemistry: AACC Press, Washington, DC. Pp 407-408.
Wu, A. (© 2006). Tietz Clinical Guide to Laboratory Tests, 4th Edition: Saunders Elsevier, St. Louis, MO. Pp 634-635.
(Modified 2009 March 13). About Iron. Iron Disorders Institute [On-line information]. Available online at http://www.irondisorders.org/Disorders/about.asp. Accessed June 2009.
(Updated 2007 August 24). Dietary Supplement Fact Sheet: Iron. NIH Office of Dietary Supplements [On-line information]. Available online at http://ods.od.nih.gov/factsheets/iron.asp. Accessed June 2009.
Rathz, D. et. al. (Updated 2009 February 02). Toxicity, Iron. eMedicine [On-line information]. Available online at http://emedicine.medscape.com/article/166933-overview. Accessed June 2009.
Chen, Y. (Updated 2009 April 05). Iron Deficiency Anemia. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000584.htm. Accessed June 2009.
Henry’s Clinical Diagnosis and Management by Laboratory Methods. 21st ed. McPherson RA and Pincus MR, eds. Philadelphia: 2007, Pg. 506-507.
(November 1, 2007) Centers for Disease Control and Prevention. Hemochromatosis, Biochemical testing. Available online at http://www.cdc.gov/ncbddd/hemochromatosis/training/diagnostic_testing/biochemical_testing.htm. Accessed October 2009.
Iron Disorders Institute. Iron Tests. PDF available for download at http://www.irondisorders.org/Forms/irontests.pdf. Accessed October 2009.
Devkota, B. (2012 October 4). Iron. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/2085704-overview#showall. Accessed April 2013.
Gersten, T. (Updated 2012 February 8). Serum iron. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003488.htm. Accessed April 2013.
(© 1995-2013). Iron and Total Iron-Binding Capacity, Serum. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Overview/34624. Accessed April 2013.
Siddique, A. and Kowdley, K. (2012). Review Article: The Iron Overload Syndromes. Medscape Reference from Aliment Pharmacol Ther. V35 (8):876-893. [On-line information]. Available online at http://www.medscape.com/viewarticle/761125. Accessed April 2013.
Spanierman, C. (Updated 2011 July 27). Iron Toxicity in Emergency Medicine. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/815213-overview. Accessed April 2013.
Boyle, J. (Updated 2012 April 12). Pediatric Iron Toxicity. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/1011689-overview. Accessed April 2013.
Pagana, K. D. & Pagana, T. J. (© 2011). Mosby’s Diagnostic and Laboratory Test Reference 10th Edition: Mosby, Inc., Saint Louis, MO. Pp 594-598.
Clarke, W., Editor (© 2011). Contemporary Practice in Clinical Chemistry 2nd Edition: AACC Press, Washington, DC. Pp 536, 597.
McPherson, R. and Pincus, M. (© 2011). Henry’s Clinical Diagnosis and Management by Laboratory Methods 22nd Edition: Elsevier Saunders, Philadelphia, PA. Pp 362-363, 427, 432-433.
Elghetany MT, Banki K. Erythrocytic disorders, in Henry’s Clinical Diagnosis and Management by Laboratory Methods, 22nd ed. McPhereson RA, Pincus MR,eds. Elsevier/Saunders: Philadelphia. Chapter 32, 2011.
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